Microsoft.CSharp.RuntimeBinder.RuntimeBinderException : Operator '&&' cannot be applied to operands of type 'bool' and 'double' about expressionevaluator

[codingseb]

Hello @spacehamster

it is because the variable E is already the Math.E constant. A small set of constants are define in ExpressionEvalauator and can not be redefine without inheritance.

The constants dictionnary :

protected IDictionary<string, object> defaultVariables = new Dictionary<string, object>(StringComparer.Ordinal)
{
    { "Pi", Math.PI },
    { "E", Math.E },
    { "null", null},
    { "true", true },
    { "false", false },
};

If you want you can modify it by inherit ExpressionEvaluator :
See Live example here

class XExpressionEvaluator : ExpressionEvaluator
{
    public XExpressionEvaluator()
    {
        defaultVariables.Remove("E");   
    }
}
//...

XExpressionEvaluator evaluator = new XExpressionEvaluator();
evaluator.Variables = new Dictionary<string, object>()
{
    { "A", true },
    { "B", false },
    { "C", false },
    { "E", true },
};

Console.WriteLine(evaluator.Evaluate("(A&&B&&C)||(A&&B)||(A&&E&&C)"));

[spacehamster]

That works. Thanks a lot!